Neuroanatomy wk 1 Flashcards
(125 cards)
1
Q
What denotes the transition from infra to supra tentorial?
A
mammillary bodies
2
Q
What is the medial projection of the cerebral cortex?
A
uncus
3
Q
What is the infolding of cerebral cortex?
A
insula
4
Q
Where does the lateral geniculate nucleus of the thalamus send afferent fibers?
A
Primary visual cortex
5
Q
Where does the medial geniculate nucleus of the thalamus send afferent fibers?
A
Primary auditory cortex
6
Q
What allows different parts of the same hemisphere to communicate?
A
corona radiata
7
Q
What allows communication from the cerebral cortex to the white matter of the brain stem?
A
internal capsule
8
Q
What separates the fluid from the two lateral ventricles?
A
septum pellucidum
9
Q
What connects the lateral ventricles to the 3rd ventricle?
A
Intraventricular foramen/Foramen of Monro
10
Q
Individual nuclei of the thalamus have reciprocal projections with…
A
cerebral cortex
11
Q
If there is pathology in the posterior hypothalamus, what syndrome might occur?
A
Horner’s syndrome
12
Q
Mammillary bodies functional consideration includes…
A
memory impairment, amnesia
13
Q
What information do superior colliculi collect?
A
visual stimuli from retina, auditory and somatosensory stimuli, cortical input
14
Q
What job does the superior colliculi serve?
A
eye movements, motor/visual reflex
15
Q
What role does the inferior colliculi have?
A
purely auditory - injury results in loss of hearing
16
Q
Damage to the Red Nucleus will cause what?
A
ataxia and tremor
17
Q
What structure does the substantia nigra associate with?
A
cuadate and putamen nucleus of basal ganglia
18
Q
What nuclei, when injured, results with nystagmus, vertigo, and Romberg fall?
A
vestibular nuclei
19
Q
What houses and sends out all of the climbing fibers of the cerebellum?
A
inferior olivary nucleus
20
Q
What is the purpose of the inferior olivary nucleus ?
A
motor learning
21
Q
What is the purpose of the Reticular formation?
A
visceral control
22
Q
The epidural space is filled with adipose and has venous plexus, unique because…
A
internal vertebral venous plexus has no valves
23
Q
Dura extends all the way to this level … and is tethered to the sacral hiatus by…
A
S2
Filum terminale
24
Q
The CSF space surrounded by dura, past the end of the spinal cord is called…
A
lumbar cistern
25
What are the extensions of pia mater called, one at each spinal segment?
denticulate ligaments
26
With each inferior level of the spinal cord, there is an elongation of dorsal and ventral nerve roots, creating...
cuada equina
27
What are the 5 branches from the spinal nerve proper?
1. dorsal ramus to TP
2. ventral ramus to TP
3. Recurrent meningeal coursing back through intervertebral foramen
4. gray ramus (always more medial)
5. white ramus (collectively gray and white are rami communicantes)
28
What layer around nerves is continuous with the dura mater?
epineurium
29
sarcolemma projects into muscle fibers as...
transverse (T) tubules
30
During contraction, what band of the sarcolemma is stable?
A band
31
What are the contractile proteins of the sarcolemma?
actin, myosin, tropomyosin, troponin
32
What protein binds actin, anchors actin to z lines?
alpha actinin
33
What protein binds to actin, anchors actin to Z line, and regulates the length of actin?
nebulin
34
What protein binds to actin and regulates the length of actin?
tropomodulin
35
What protein stabilizes myosin, and anchors myosin to Z line?
titin
36
What protein binds myosin, holding thick filaments in register, establishing M line?
myomesin and C protein
37
What protein forms lattic around Z line, stablizing the cross link between adjacent myofibrils?
desmin
38
What protein connects cytoskeleton of muscle fiber to surrounding ECM through the cell membrane?
dystrophin
39
immune cells in the spinal cord, around damaged tissue, forming a microglial nodule are what? What are they doing?
neuronophagia
| eating dead neurons/damaged tissue
40
What kind of injury is acute flaccid paralysis? What make this 'flaccid'?
LMN injury
| -flaccid because there is no reflex present- hyporeflexia
41
What 3 areas are LMNs in?
1. motor nuclei of CN
2. lateral horn of SC (ANS)
3. Ventral horn of SC
42
Within the ventral horn, what are three types of LMNs?
1. alpha
2. Beta
3. gamma
43
What type of LMN are innervating extrafusal fibers forming motor end plates?
alpha motor neuron
44
the total number of muscle fibers innervated by a single alpha motor neuron is considered...
motor unit
45
smaller motor units control...
more refined movements
46
motor units of alpha MN is always (excitatory/inhibitory). What are the three possible inputs?
excitatory
1. UMN
2. neuron in DRG (sensory)
3. interneuron (MC)
47
What is the sensory structure responding to length/contractile state along with rate of muscle length change?
spindle apparatus
48
How is a spindle apparatus composed in regard to intrafusal and extrafusal fibers?
several intrafusal muscle fibers are encapsulated and embedded in parallel with extrafusal muscle fibers
contractile parts at the end of muscle spindle fibers; also anchored to extrafusal fibers here
49
What are two types of intrafusal muscle fibers? How many are there per spindle apparatus?
```
chain fibers (5-7 per spindle, stiffer)
bag fibers (1-2 per spindle)
```
50
What is the equitorial region of intrafusal fibers?
the middle of the fiber, the contact site for sensory neurons
51
group Ia fibers/ primary afferents wrap around equitorial region of intrafusal fibers and some bag fibers in order to...
These fibers are considered (dynamic/static) and are (myelinated/unmyelinated).
get information on muscle length and rate of change
dynamic
myelinated
52
group II/ secondary afferents are located....
These are considered (dynamic/static). They give information on...
at the junction b/t contractile proteins and equitorial region
static
length of muscle, indirectly about body position
53
Chain and bag fibers are both innervated by....
gamma motor neurons
54
The very tip of bag fibers are innervated by...
beta motor neurons
55
Beta motor neurons innervate what type of fibers?
intrafusal and extrafusal
56
DTR/Myotatic stretch reflex occurs when stimulus of the spindle apparatus generates an AP in Ia or II sending the AP on to the Dorsal root, pseudounipolar soma, central process, dorsal horn, and down to form excitatory synapse on LMN innervating the same muscle.
This is called...
Autogenic excitation
57
In autogenic excitation, muscle contraction occurs (CL, ipsi) to side of reflex and afferents send collateral axon to inhibitory interneuron which will synapse on LMN of ....
ipsilateral
antagonist muscle
58
Where is the Golgi tendon organ found?
between muscle fibers and tendon, in series with muscle
59
What type of afferent nerve endings weave through the loose collagen fibers of the golgi tendon organ?
Contraction of muscle applies tension and activates the neuronal response. Responds relative to...
Ib afferent nerve endings
levels of muscle force
60
When does autogenic inhibition occur?
when Ib afferent nerve ending is activated - central process synapses onto an inhibitory interneuron, which in turn synapses on LMN to same muscle
61
When a golgi tendon organ is working, it inhibits (ipsilateral/CL) and stimulates (ipsilateral/CL).
inhibits ipsilateral
| stimulates CL
62
autogenic inhibition also sends out collateral Ib to excitatory interneurons to allow...
LMN to innervate antagonist
63
From the DRG, this tract of white matter carries discrete pain and temp. It is part of the spinothalamic pathway and allows ascending and descending signals. It is found in the outer edge, the 'cap', of the dorsal horn.
Lissauer's Tract (Dorsolateral Tract)
64
What fibers synapse in the Substantia Gelatinosa? What info do they carry? What pathway are they a part of?
- C fibers and A fibers
- carrying pain, temp, and light touch
- part of spinothalamic pathway
65
Where do mechanical and temperature afferents synapse in the dorsal horn as part of the spinothalamic pathway?
Nucleus proprius
66
The most proximal relay center of the dorsal horn is....
The input to here is from...
What pathway is it part of?
Dorsal Nucleus of Clarke
- proprioception from Golgi and spindle
- part of the spinocerebellar pathway
67
What is the arrangement of LMNs in the ventral horn?
flexors are dorsal
extensors are ventral
going to distal extremities are lateral
going to proximal appendages are medial
68
What is Rexed Lamina I?
Nucleus Marginalis
69
What is Rexed Lamina II?
Substantia Gelatinosa
70
What is the corresponding Rexed Lamina for the Nucleus Proprius?
IV
71
What is the corresponding Rexed Lamina for the Dorsal Nucleus?
VI
72
Rexed Lamina VII, VIII, and IX are for...
LMNs
73
Rexed Lamina X is for the...
commissural region
74
The area immediately surrounding the central canal of the SC, allowing the R and L sides to communicate is called...
commissural region - dorsal grey commissure or ventral grey commissure
75
On the anterior side of the spinal cord, there is a white commissure that carries fibers from what two pathways?
Anterior Corticospinal pathway and Lateral Spinothalamic Pathway
76
Lateral horn in the spinal cord appears below what level?
T2
77
What are Renshaw cells? How do they work?
inhibitory interneurons
an axon from alpha MNs sends a collateral to Renshaw cell which will send inhibitory signals back onto the alpha MN. This is associated with group Ia afferents
78
Without Renshaw cells, we would have ....
hyperreflexia
79
UMN show.... where a direct excitatory synapse onto an alpha MN and a second excitatory synapse onto an interneuron. this interneuron then forms an inhibitory synapse with alpha MN innervating the antagonist muscle to the original excitatory alpha MN.
Disynaptic inhibition
80
anterior to the precentral sulcus, in the posterior parts of the middle and inferior frontal gyri, is the area known as the ...
pre-motor cortex
81
anterior to the precentral sulcus, in the posterior part of the superior frontal gyrus, is the area known as ...
supplementary motor cortex
82
the corticobulbar tract goes through which part of the internal capsule?
genu
83
the corticospinal tract goes through which part of the internal capsule? How are the arms/trunk/legs organized?
posterior limb/posterior crus
| - arms and hands anterior, trunk middle, and legs posterior
84
in the midbrain, the corticospinal tract forms the central portion of...
How are the arms/trunks/legs organized?
crus cerebri
| - arms/trunks/legs are medial to lateral
85
In the basis pontis, there is some white matter arranged horizontally around grey matter. The grey matter is...
pontine nuclei
86
following the cortico-ponto-cerebellar pathway from the crus cerebri to the pontine nuclei, it will then go through the transverse axons to... and become...
middle cerebellar peduncle
| becoming the majority of the arbor vitae
87
What tract makes up the majority of the medullary pyramids?
corticospinal tract
88
What is the pathway of the corticospinal tract from the primary motor cortex through the medulla?
PMC
- posterior crus of internal capsule
- - middle crus of crus cerebri
- --through pons
- ---makes the majority of the medullary pyramids
- ---- motor decussation inferior to pyramids
89
How many of the corticospinal tract fibers decussate at the motor decussation? What are the groups named?
90%
those that do cross over -> Lateral corticospinal tract
those that do not cross over -> ventral/anterior corticospinal tract
90
A lesion in the corticospinal tract above the pyramidal decussation will cause...
contralateral hemiplegia
91
A lesion in the corticospinal tract below the pyramidal decussation will cause ...
ipsilateral hemiplegia
92
Where in the spinal cord is the lateral corticospinal tract located?
dorsal portion of lateral column of white matter, inferior to the DH of grey matter
93
Where in the spinal cord is the anterior corticospinal tract located?
in the ventral column of white matter, immediately adjacent to the median fissure
94
the lateral corticospinal tract goes to LMNs where?
in the lateral part of the VH, to upper limb and distal trunk
95
the anterior corticospinal tract goes to LMNs where?
in the medial part of the VH, to lower leg and proximal trunk
96
With lateral sclerosis, plaque forms over the corticospinal tract, especially the lateral CS tract. This causes a disconnect between the UMN and the LMN. LMN to skeletal muscle is still intact, so there is still sensory feedback to LMN. This ultimately causes symptoms of...
rigid paralysis and hyperreflexia
it does not turn off Golgi or spindle
97
What is the pathway of the Corticobulbar tract from the primary motor cortex through the medullary pyramids?
PMC
- genu of internal capsule
- - radiates to brainstem nuclei of all Cranial motor nerves
- -distal end extends down to pyramidal system
98
What three pathways of the extrapyramidal system do not decussate?
Medial Longitudinal Fasciculus
Reticulospinal
Vestibulospinal
99
Where does the tectospinal tract decussate?
dorsal tegmental
100
Where does the rubrospinal tract decussate?
ventral tegmental
101
What tract does visual and equilibrium reflexes to the neck and UE?
medial longitudinal fasciculus
102
What tract carries spinal visual reflexes?
tectospinal
103
What tract does postural reflexes?
vestibulospinal
104
What tract does postural body tone?
rubrospinal
105
What tract can become voluntary should the body require it? What else does it normally do?
reticulospinal
also does reflex activity and muscle tone
106
The tectospinal tract originates where?
colliculi in midbrain tectum
107
Where does the MLF originate?
vestibular nucleus and superior colliculus
108
the spinothalamic pathway is also known as...
anterolateral system
109
C and A delta fibers from periphery go to the soma in the DRG and go into Lissauer's tract. Here they go up or down and synapse on Rexed Lamina in the DH. Where do they go next, as they carry pain and temperature sensations?
through the DH, across White Commissure, through the VH to the AnteroLateral system where they ascend through the spinal cord to the pons
110
The anterolateral system at the pons changes names to... and continues to...
spinal lemniscus
continues to the ventroposterolateral (VPL) nucleus of the thalamus
111
after coming from the anterolateral system and spinal lemniscus, VPL neurons are 3rd order and project to...
primary somatosensory cortex in post-central gyrus
112
When does decussation occur in the spinothalamic/anterolateral system?
immediately, at same level as incoming stimulus
113
What will occur to areas above and below a syrinx that has compressed and obliterated commissural fibers?
both inferior and above syrinx, fibers will be intact
114
What is the main synaptic center for the spinothalamic/anterolateral system?
substantia gelatinosa
115
Modulating fibers from descending origin or sensory fibers (Ia muscle spindle) can help reduce pain if synapses are in substantia gelatinosa or nucleus proprius. However, in .... location, they cannot be modulated and it can be a source of intractable pain.
Marginal nucleus/Lissauer's tract
116
The dorsal column pathway transmits...
discriminatory touch, conscious proprioception, and vibrational stimuli
117
The cuneate fasciculus is present in the spinal cord starting at level...
T6 and up
118
Where do the gracile and cuneate fasciculi go to synapse and then to decussate?
caudal medulla oblongata to synapse onto respective nucleus then course ventromedially and decussate as internal arcuate fibers
this decussation occurs more rostral than pyramidal decussation
119
decussated fibers of the internal arcuate, from the cuneate and gracile fasciculi, coalesce just off midline immediately dorsal to the medullary pyramids and is now named...
medial lemniscus
120
The medial lemniscus, starting in the medulla, dorsal to the pyramids goes where?
through the brainstem to the VPL nucleus of thalamus where they synapse. then they travel through the posterior crus of the internal capsule to the primary somatosensory cortex in the postcentral gyrus
121
Brown-Sequard Syndrome is a result of hemisectioning of the spinal cord that results in this pattern below the hemisection level...
1. loss of ipsilateral discriminatory touch and conscious proprioception
2. loss of CL pain and temp sensation
3. loss of ipsilateral motor control
122
The spinal lemniscus and medial lemniscus abut each other within the pons. Both are in the.... between....
tegmentum
| ventral to cerebral aqueduct but dorsal to basis pontis
123
The spinal lemniscus abuts the .... of the medial lemniscus
lateral end
124
the medial lemniscus in the midbrain is along the lateral surface of the... while the spinal lemniscus courses deep to...
red nucleus
inferior cerebellar peduncle
125
In a secondary pain pathway, the spinoreticular pathwa, synapses are formed in the medullary reticular formation and ascend to thalamus to synapse in... and then go...
in centromedian nucleus and more broadly in laminar nuclei, then broadly to cerebral cortex
this prevents localization of pain stimulus
